Stretch Blow Molding Preform Heating with Variable Station Switch-Off
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Solution Overview
Problem
Existing stretch blow molding machines operate with constant output and lack flexibility to adjust production without causing rejects when downstream units fail or require output control, such as during label changes or startup of filling devices.
Innovation Solution
A device with a blocking mechanism to interrupt the supply of plastic preforms to the heating device, allowing individual heating elements to heat preforms independently and create gaps in the transport line, enabling flexible output control and reducing rejects by temporarily stopping or adjusting the heating process based on downstream unit availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stretch blow molding machine operates with constant output and all stations are firmly linked, then the production process is stable and continuous, but individual stations cannot be switched off during operation without losing plastic preforms and creating rejects
Solution Approach 1:
The production line is divided into independently controllable stations (heating device, blow molding machine, downstream units). Each station can be individually activated or deactivated without affecting the entire system, allowing selective operation of heating and blow molding while downstream units are maintained in standby mode.
Solution Approach 2:
The system transitions from a static, fixed-speed configuration to a dynamic system where station activation is variable. The control device enables real-time switching between different operational states (all stations active, selective station activation, standby mode) based on downstream unit availability.
2Productivity
If downstream units fail or require output control (e.g., label changes, filling device startup), then the production process must be adjusted, but constant machine speed operation causes preforms to be lost as rejects
Solution Approach 1:
The blocking device is activated in advance before downstream units fail or require adjustment. This preemptive action temporarily halts preform supply to the heating device, preventing the accumulation of preforms that would otherwise become rejects when downstream units are unavailable.
Solution Approach 2:
The control device monitors the operational status of downstream units and provides feedback to the blocking device. When downstream units are unavailable or require adjustment, the control device automatically activates the blocking device to synchronize production rates, eliminating the need for manual intervention and preform waste.
3Device complexity
If all plastic preforms are guided past all heating elements in a row, then the heating process is continuous and simple, but individual heating control is not possible and thermal influence between adjacent preforms cannot be prevented
Solution Approach 1:
The heating process is segmented into individual heating zones, each with dedicated heating elements. This allows selective activation of specific heating elements corresponding to individual preforms or small groups, enabling independent temperature control for each position in the heating sequence.
Solution Approach 2:
Different heating zones can be operated with different temperature settings and durations tailored to specific preform positions. The system applies localized heating control, where each heating element or group can be independently adjusted to optimize heating quality without affecting other zones.
4Stability of the object's composition
If the machine operates in a block with all units coupled and speeds adapted to one another, then the production flow is synchronized, but flexibility to adjust output at individual stations is lost
Solution Approach 1:
The system enables dynamic adjustment of production flow at different stations. While maintaining synchronized operation during normal production, the control device allows temporary decoupling of stations through selective activation/deactivation, enabling individual output adjustment without disrupting overall production synchronization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces rejects by allowing individual control over the heating and shaping process, enabling continuous operation at constant machine speed even when downstream units fail or require adjustments, and ensures efficient use of resources by preventing unnecessary heating and processing.
Implementation Method 1
a heating device (2) for heating the plastic preforms (10)
Data Source
Figure 1~2
AI summary
A device (1) for manufacturing plastic containers comprises a heating device (2) for heating plastic preforms (10) and a forming device (4) downstream of the heating device (2) in a transport direction for the plastic preforms, for forming the plastic preforms into plastic containers, and a transport device (6) which transports the plastic preforms individually through the heating device (2) by means of a plurality of transport elements (14). The device (1) includes a locking device (8) for temporarily interrupting the supply of the plastic preforms (10) to the heating device (2), wherein the locking device (8) allows for the interruption of the supply for individual plastic preforms (10). According to the invention, the heating device (2) has a plurality of heating elements (18) for heating individual plastic preforms (10) or groups of plastic preforms (10).